---
title: Langfuse
slug: /integrations-langfuse
---

import Tabs from '@theme/Tabs';
import TabItem from '@theme/TabItem';

[Langfuse](https://langfuse.com) is an open-source platform for LLM observability. It provides tracing and monitoring capabilities for AI applications, helping developers debug, analyze, and optimize their AI systems. Langfuse integrates with various tools and frameworks, including workflow builders and runtimes like Langflow.

This guide explains how to configure Langflow to collect [tracing](https://langfuse.com/docs/tracing) data about your flow executions and automatically send the data to Langfuse.

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## Prerequisites

- An account in a [Langfuse Cloud](https://cloud.langfuse.com) or [Langfuse self-hosted](https://langfuse.com/self-hosting) instance
- A [running Langflow server](/get-started-installation) with a [flow](/concepts-flows) that you want to trace

:::tip
If you need a flow to test the Langfuse integration, see the [Langflow quickstart](/get-started-quickstart).
:::

## Set Langfuse credentials as environment variables {#langfuse-credentials}

1. Create a set of [Langfuse API keys](https://langfuse.com/faq/all/where-are-langfuse-api-keys).

2. Copy the following API key information:

    - Secret Key
    - Public Key
    - Host URL

3. Set your Langfuse project credentials as environment variables in the same environment where you run Langflow.

    In the following examples, replace `SECRET_KEY`, `PUBLIC_KEY`, and `HOST_URL` with your API key details from Langfuse.

    <Tabs>
    <TabItem value="linux-macos" label="Linux or macOS" default>

    These commands set the environment variables in a Linux or macOS terminal session:

    ```
    export LANGFUSE_SECRET_KEY=SECRET_KEY
    export LANGFUSE_PUBLIC_KEY=PUBLIC_KEY
    export LANGFUSE_HOST=HOST_URL
    ```

    </TabItem>
    <TabItem value="windows" label="Windows">

    These commands set the environment variables in a Windows command prompt session:

    ```
    set LANGFUSE_SECRET_KEY=SECRET_KEY
    set LANGFUSE_PUBLIC_KEY=PUBLIC_KEY
    set LANGFUSE_HOST=HOST_URL
    ```

    </TabItem>
    </Tabs>

## Start Langflow and view traces in Langfuse

1. Start Langflow in the same environment where you set the Langfuse environment variables:

    ```bash
    uv run langflow run
    ```

2. Run a flow.

    Langflow automatically collects and sends tracing data about the flow execution to Langfuse.

3. View the collected data in your [Langfuse dashboard](https://langfuse.com/docs/analytics/overview).

    Langfuse also provides a [public live trace example dashboard](https://cloud.langfuse.com/project/cm0nywmaa005c3ol2msoisiho/traces/f016ae6d-4527-43f5-93ba-9d78388cd3d9).

## Disable Langfuse tracing

To disable the Langfuse integration, remove the [Langfuse environment variables](#langfuse-credentials), and then restart Langflow.

## Run Langfuse and Langflow with Docker Compose

As an alternative to the previous setup, particularly for self-hosted Langfuse, you can run both services with Docker Compose.

1. Create a set of [Langfuse API keys](https://langfuse.com/faq/all/where-are-langfuse-api-keys).

2. Copy the following API key information:

    - Secret Key
    - Public Key
    - Host URL

3. Add your Langflow credentials to your Langflow `docker-compose.yml` file in the `environment` section.

    The following example is based on the [example `docker-compose.yml`](https://github.com/langflow-ai/langflow/blob/main/docker_example/docker-compose.yml).

    ```yml
    services:
      langflow:
        image: langflowai/langflow:latest # or another version tag on https://hub.docker.com/r/langflowai/langflow
        pull_policy: always               # set to 'always' when using 'latest' image
        ports:
          - "7860:7860"
        depends_on:
          - postgres
        environment:
          - LANGFLOW_DATABASE_URL=postgresql://langflow:langflow@postgres:5432/langflow
          # This variable defines where the logs, file storage, monitor data and secret keys are stored.
          - LANGFLOW_CONFIG_DIR=app/langflow
          - LANGFUSE_SECRET_KEY=sk-...
          - LANGFUSE_PUBLIC_KEY=pk-...
          - LANGFUSE_HOST=https://us.cloud.langfuse.com
        volumes:
          - langflow-data:/app/langflow

      postgres:
        image: postgres:16
        environment:
          POSTGRES_USER: langflow
          POSTGRES_PASSWORD: langflow
          POSTGRES_DB: langflow
        ports:
          - "5432:5432"
        volumes:
          - langflow-postgres:/var/lib/postgresql/data

    volumes:
      langflow-postgres:
      langflow-data:
    ```

4. Start the Docker container:

    ```text
    docker-compose up
    ```

5. To confirm Langfuse is connected to your Langflow container, run the following command:

    ```sh
    docker compose exec langflow python -c "import requests, os; addr = os.environ.get('LANGFUSE_HOST'); print(addr); res = requests.get(addr, timeout=5); print(res.status_code)"
    ```

    If there is an error, make sure you have set the `LANGFUSE_HOST` environment variable in your terminal session.

    Output similar to the following indicates success:

    ```text
    https://us.cloud.langfuse.com
    200
    ```

## See also

* [Langfuse GitHub repository](https://github.com/langfuse/langfuse)